u and v wind component values ?

From: Ed Martino <Ed.Martino_at_nyahnyahspammersnyahnyah>
Date: Wed Apr 27 2011 - 15:44:49 MDT

Hi

I am having some difficulty plotting and interpreting wind vectors using
the NCEP reanalysis files. The data values seem too large, I think?.

I used ncl's "min" and "max" functions to generate variable summaries
for u and v winds.

The NCEP u and v wind component files are
uwnd.mon.mean.p.nc
vwnd.mon.mean.p.nc

I used the following statement to generate the output copied below.
print("min/max slp_anom = " + min(slp_anom) + "/" + max(slp_anom))

Magnitude of min and max values seem too large as indicated by the
copied output of variable summaries below.
Do min and max values seem OK? Am I missing something in interpreting
the variable values?

Thanks.
Ed

*************************************************************************
Variable: u
Type: short
Total Size: 271272672 bytes
             135636336 values
Number of Dimensions: 4
Dimensions and sizes: [time | 759] x [level | 17] x [lat | 73] x [lon
| 144]
Coordinates:
             time: [17067072..17620752]
             level: [1000..10]
             lat: [90..-90]
             lon: [ 0..357.5]
Number Of Attributes: 16
   long_name : Monthly mean u wind
   actual_range : ( -66.37, 124.4 )
   unpacked_valid_range : ( -125, 160 )
   units : m/s
   add_offset : 202.65
   scale_factor : 0.01
   missing_value : 32766
   precision : 2
   least_significant_digit : 1
   var_desc : u-wind
   dataset : CDC Derived NCEP Reanalysis Products
   level_desc : Multiple levels
   statistic : Mean
   parent_stat : Other
   valid_range : ( -32765, -4265 )
   _FillValue : 32766
(0) min/max u = -26902/-7825

Variable: v
Type: short
Total Size: 271272672 bytes
             135636336 values
Number of Dimensions: 4
Dimensions and sizes: [time | 759] x [level | 17] x [lat | 73] x [lon
| 144]
Coordinates:
             time: [17067072..17620752]
             level: [1000..10]
             lat: [90..-90]
             lon: [ 0..357.5]
Number Of Attributes: 16
   long_name : Monthly mean v wind
   actual_range : ( -66.65, 66.39 )
   unpacked_valid_range : ( -125, 160 )
   units : m/s
   add_offset : 202.65
   scale_factor : 0.01
   missing_value : 32766
   precision : 2
   least_significant_digit : 1
   var_desc : v-wind
   dataset : CDC Derived NCEP Reanalysis Products
   level_desc : Multiple levels
   statistic : Mean
   parent_stat : Other
   valid_range : ( -32765, -4265 )
   _FillValue : 32766
(0) min/max v = -26930/-13626

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Received on Wed Apr 27 15:44:58 2011

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